Lattice Boltzmann (LB) schemes have emerged in the
past years as a valid tool for simulating the dynamics
of complex fluids. Such schemes differ substantially
from Continuos Fluids Dynamics as they mimic systems at
the mesoscopic level. Various people at the CCS have
been involved in the development of LB3D, a bottom up
implementation of such technique. LB3D uses MPI
libraries in order to run in parallel. It has been
tested on a variety of resources and was awarded a gold
star for scaling up to 1024 processors. For some values
of the densities and interactions parameters, an
amphiphilic fluids can assemble into a long range
ordered structure, or a crystal, known as gyroid (fig.
1).

Fig 1. The discovery of the gyroid has led to
the TeraGyroid project, where massive simulations
of gyroids were performed on the U.S. TeraGrid in
order to inspect the dynamics of defects in such a
crystal.

In particular, LB3D does not impose any
"macroscopic" constraints to the dynamics of the
system. This is different from top down Lattice
Boltzmann models were the dynamics is dictated by an
imposed, well crafted, stress tensor. It is therefore
natural to study the macroscopic parameters of the
fluids under different conditions, such as steady and
oscillatory shear. Such study is ongoing and it has
been possible to demonstrate Non-Newtonian behaviour of
the gyroid and a viscoelastic behaviour.

Sheared equilibrium mesophases

The same "experiments" will be repeated for a ternary
mixture similar to the gyroid without long range order
to assess how much of this behavior is to credit to the
crystal structure of the fluid.

LB3D is able to simulate ternary mixtures, and
therefore a careful investigation of the effect of
surfactant in the spinodal decomposition is under way.
Particular attention is given to the dynamical scaling
law and to the domain growth in different regimes.
Also, effect of steady/oscillatory shear on spinodal
decomposition is studied.